1. Technical Field
This disclosure relates generally to rotational equipment and, more particularly, to an assembly including a bearing and a rotating seal element.
2. Background Information
A seal assembly is typically used in rotational equipment to provide a seal between regions of high and low fluid pressure and/or temperature. A seal assembly may be used, for example, to provide a gas and/or liquid seal between a stator and a rotor of a turbine engine, a pump, a compressor, a turbine of a hydro-electric or wind generator, as well as various other types of rotational equipment.
A seal assembly for a turbine engine may include a lift-off face seal that is connected to a seal support. The seal support is connected to a stator with a plurality of fasteners. The seal support includes a plurality of coil springs that bias the face seal axially against a forward side of a seal landing. The seal landing is mounted on a shaft. The seal landing has an aft side that axially contacts an inner race of a bearing, which supports the shaft.
During turbine engine operation, a side of the face seal and the forward side of the seal landing may be exposed to relatively hot air. A portion of this air may be directed into passages within the face seal to provide a film of air between the face seal and the seal landing. Heat energy may be transferred from the air into the seal landing, which may significantly increase the temperature of the seal landing. A portion of relatively cool lubrication oil may travel axially from the bearing onto the aft side of the seal landing. This lubrication oil may transfer the heat energy out of and thereby cool the seal landing. However, since air and lubrication oil typically have different heat transfer coefficients, the aft side of the seal landing may become significantly cooler than the forward side. The seal landing therefore may be subject to a relatively non-uniform temperature gradient, which may cause the seal landing to cone away from the face seal. Such coning may increase leakage between the face seal and the seal landing.
There is a need in the art for an improved seal assembly.